From Halopedia, the Halo wiki
The Nephis Coalition actively extracts zenostium plasma from the Hephestes-Nephis flux tube that exists between the interacting magnetospheres of the gas giant and its moon. The valuable superconducting zenostium that the coalition pulls from the tube is used as a critical component in the manufacture of antigravity plates. Owing to the importance of the Nephis Coalition to the United Nations Space Command, any threat of civil unrest on Nephis or commercial rivalry between it and its competitors is taken very seriously.
List of appearances
- Halo: Retribution (First mentioned)
- Halo: Retribution, Chapter 2